In her recent article entitled “How 30 years of no-till gets this farmer higher yields than average”, Ananda Fitzsimmons of Regeneration Canada highlights the many benefits of no-till farming. Avoiding physical disruption of the soil as much as possible through use of no-till and direct seeding methods is indeed a huge advance for agriculture. No-till contributes massively to reductions in soil erosion and pollution, helps conserve moisture in dry conditions, and can increase soil organic matter.
However, I was disappointed to see the organic vs. no-till debate and the suggestion that one might be better than the other brought up under the banner of regenerative agriculture. Reducing or eliminating tillage is only one of the principles of regenerative agriculture. The other principles—keeping soil covered, maintaining living roots, adding diversity, and integrating livestock—are what differentiate regenerative agriculture from mainstream organic and no-till systems.
While it is true that some organic farms rely heavily on tillage, it is also true that some no-till farms rely heavily on herbicides. The fact of the matter is that both tillage and herbicides are forms of disturbance. They disrupt the natural processes of ecological succession that cause colonizing plants (AKA weeds) to grow in places and at times when there are resources available for growth. Disturbance is what keeps our farm fields from reverting back to prairies or forests over time. As long as we consumers ask farmers to grow the annual crops we love so much, disturbance will be a necessary part of farming.
Whether this disturbance is caused by a tillage implement, a herbicide, a fire, a rooting pig or a grazing cow is somewhat beside the point. Disturbance disturbs! Tillage disrupts plant growth physically, while herbicides disrupt it chemically. Research has shown both to have negative effects on soil organisms such as earthworms and mycorrhizal fungi.
What is more important, in my view, is what happens before and after the disturbance to help the soil recover from the disturbance. Physical protection from erosion is indeed important, but so is providing conditions that support the growth and function of soil organisms that help form soil organic matter and stable soil aggregates. These processes are complex and are not governed by false dichotomies of herbicides vs. tillage or any other pair of differing management practices. For example, in a long-term study in Michigan, soil organic carbon increased more in a tilled organic system than in a conventional system with minimal tillage (Grandy and Kallenbach, 2015). The likely cause? Frequent incorporation of cover crops in the organic system seems to have provided better support for the soil microorganisms, which eventually turned into soil organic matter themselves. Anecdotally, I have seen the effects of wind and water erosion in both organic and no-till fields. I have also seen very healthy populations of earthworms—an indicator claimed by both organic and no-till proponents as a sure sign of soil health in their own systems—in fields where both tillage and herbicides were used regularly! It would seem that the evidence on exactly which practices create a healthy soil is as clear as mud.
According to LaCanne and Lundgren (2018), regenerative farms select from a suite of practices based on a set of principles. In their study, only one farm out of ten used all five of their criteria to be considered regenerative. Farms using both organic and no-till practices were also considered regenerative when they used cover crops and grazing livestock and avoided insecticides.
In her article, Ananda Fitzsimmons wonders whether it is possible that a thriving microbiome can bio-degrade molecules of glyphosate and its derivatives. I believe it is also worth asking whether it is possible that a thriving soil microbiome can help soil recover from tillage. I would add to her very good question: Perhaps the question about the harms of certain chemicals—and tillage—needs to be more nuanced? We all need to ask ourselves some difficult questions when any “solution” to controlling weeds involves more disturbance of any kind.
Lately I have seen the “big tent” of regenerative agriculture and soil health bring organic and conventional farmers together in a way I never imagined possible. They attend conferences together, visit each other’s farms, and even serve on farmer panels side by side, discussing topics such as intercropping, cover crops and mob grazing practices. They seem to recognize that there are bigger fish to fry than which type of disturbance is used to keep weeds in check. Rather, they are focusing on how to minimize the need for disturbance in the first place, how to use it strategically when needed, and how to help soil withstand and recover from it. It is in the other principles of regenerative agriculture—keeping soil covered, maintaining living roots, promoting diversity and integrating crops and livestock—that these farmers see opportunities to improve their farming systems for themselves, consumers and future generations.
Comparing organic and no-till to see which is “better” (or really, which is the lesser of two evils) just adds unnecessary fuel to this old fire. I am still hopeful that regenerative agriculture will be the soaking rain that can put this fire out and redirect our attention to the ways that all farmers can enhance the health of our soils and agroecosystems.
Grandy, S. and C. Kallenbach. Microbes drive soil organic matter accumulation in organic cropping systems. Organic Agriculture Research Symposium. https://www.youtube.com/watch?v=9Djf9eie97k
LaCanne, C.E. and J.G. Lundgren. 2018. Regenerative agriculture: merging farming and natural resource conservation profitably. PeerJ 6:e4428; DOI 10.7717/peerj.4428 peerj.com/articles/4428/